s = input()
index_c = []
index_w = []
for x in s:
    if x == 'c':
        index_c.append(s.find(x))
        s = s.replace('c', '0', 1)
    elif x == 'w':
        index_w.append(s.find(x))
        s = s.replace('w', '1', 1)

len_cww = []
for c in index_c:
    if len(index_c) == 0 or len(index_w) < 2:
        print(-1)
        break
    elif c < index_w[-2]:
        for w in range(len(index_w)):
            if c < index_w[w]:
                len_cww.append(index_w[w+1] - c + 1)
                break
if len(len_cww) == 0:
    print(-1)
else:
    print(max(len_cww))